Analysis of a biological sample includes the step of placing the biological sample on a substrate, such as a microscope slide, for examination. Once placed on the substrate, the biological sample may be smeared across the substrate, thereby forming a wider and thinner layer of the biological sample to enable more efficient processing, imaging and examination of components of the biological sample. However, non-uniformity may lead to problems with imaging and examination, thereby leading to errors and incorrect analysis. As a result, practitioners, researchers, and those working with suspensions or solutions continue to seek an apparatus and method for repeatedly and uniformly spreading a biological sample, a solution, or a suspension across a substrate.